cherrypick Change-Id: I09778f0795dcb5d87cde652bfb7d514a0dfd9782

docs: add documentation about market multiple apk support

Change-Id: I65815f86890ca51009bdcfa89ab7733bba2881eb

6 files changed, 823 insertions, 108 deletions

diff --git a/docs/html/guide/appendix/market-filters.jd b/docs/html/guide/appendix/market-filters.jd
index ef1deba..dc79d95 100644
--- a/docs/html/guide/appendix/market-filters.jd
+++ b/docs/html/guide/appendix/market-filters.jd
@@ -13,10 +13,15 @@ manifest file to the configurations defined by the device, as well as other fact
 
 <h2>In this document</h2>
 
-<ol> <li><a href="#how-filters-work">How Filters Work in Android Market</a></li>
-<li><a href="#manifest-filters">Filtering based on Manifest File Elements</a></li>
-<li><a href="#other-filters">Other Filters</a></li> 
-<li><a href="#advanced-filters">Advanced Manifest Filters</a></li>
+<ol>
+  <li><a href="#how-filters-work">How Filters Work in Android Market</a></li>
+  <li><a href="#manifest-filters">Filtering based on Manifest Elements</a>
+    <ol>
+      <li><a href="#advanced-filters">Advanced manifest filters</a></li>
+    </ol>
+  </li>
+  <li><a href="#other-filters">Other Filters</a></li>
+  <li><a href="#MultiApks">Publishing Multiple APKs with Different Filters</a></li>
 </ol>
 
 <h2>See also</h2>
@@ -39,75 +44,72 @@ href="{@docRoot}guide/topics/manifest/uses-permission-element.html">&lt;uses-per
 href="{@docRoot}guide/topics/manifest/uses-sdk-element.html">&lt;uses-sdk&gt;</code></a></li>
 </ol>
 
-<div id="qv-extra"> <img id="rule" src="{@docRoot}assets/images/grad-rule-qv.png">
-<div id="qv-sub-rule"> <img src="{@docRoot}assets/images/icon_market.jpg"
-style="float:left;margin:0;padding:0;"> <p style="color:#669999;">Interested in
-publishing your app on Android Market?</p> <a id="publish-link"
-href="http://market.android.com/publish">Go to Android Market &raquo;</a> </div>
+<div id="qv-extra">
+  <img id="rule" src="{@docRoot}assets/images/grad-rule-qv.png">
+  <div id="qv-sub-rule">
+    <img src="{@docRoot}assets/images/icon_market.jpg" style="float:left;margin:0;padding:0 5px;">
+    <h2 style="color:#669999;">Interested in publishing your app on Android Market?</h2> 
+    <p><a id="publish-link"
+href="http://market.android.com/publish">Go to Android Market</a> to create a publisher
+account and upload your app.</p></div>
 </div>
 
 </div>
 </div>
 
 
-<p>When a user searches or browses in Android Market, the results are filtered based on which
-applications are compatible with the user's device. For example, if an application requires a
-trackball (as specified in the manifest file), then Android Market will not show
-the app on any device that does not have a trackball.</p>
+<p>When a user searches or browses in Android Market on an Android device, the results are filtered
+based on which applications are compatible with that device. For example, if an application
+requires a camera (as specified in the application manifest file), then Android Market will not show
+the app on any device that does not have a camera.</p>
 
-<p>The manifest file and the device's hardware and features are only part of how applications are
-filtered&mdash;filtering might also depend on the country and carrier, the presence or absence of a
-SIM card, and other factors. </p>
+<p>Declarations in the manifest file that are compared to the device's configuration is not the
+only part of how applications are filtered. Filtering might also occur due to the user's country and
+carrier, the presence or absence of a SIM card, and other factors. </p>
 
-<p>Changes to the Android Market filters are independent of changes 
-to the Android platform itself. This document will be updated periodically to reflect 
-any changes that affect the way Android Market filters applications.</p>
+<p>Changes to the Android Market filters are independent of changes to the Android platform itself.
+This document is updated periodically to reflect any changes that affect the way Android Market
+filters applications.</p>
 
 
 <h2 id="how-filters-work">How Filters Work in Android Market</h2>
 
 <p>Android Market uses the filter restrictions described below to determine
 whether to show your application to a user who is browsing or searching for
-applications on an Android-powered device. When determining whether to display your app,
-Market checks the device's hardware and software capabilities, as well as it's
+applications from the Android Market app. When determining whether to display your app,
+Market checks the device's hardware and software configuration, as well as it's
 carrier, location, and other characteristics. It then compares those against the
-restrictions and dependencies expressed by the application itself, in its
+restrictions and dependencies expressed by the application's
 manifest file and publishing details. If the application is
 compatible with the device according to the filter rules, Market displays the
 application to the user. Otherwise, Market hides your application from search
-results and category browsing. </p>
-
-<p>You can use the filters described below to control whether Market shows or
-hides your application to users. You can use any combination of the
-available filters for your app&mdash;for example, you can set a
-<code>minSdkVersion</code> requirement of <code>"4"</code> and set
-<code>smallScreens="false"</code> in the app, then when uploading the app to
-Market you could target European countries (carriers) only. Android Market's
-filters would prevent the application from being visible on any device that did
-not match all three of these requirements. </p>
-
- <p>A filtered app is not visible within Market, even if a user specifically requests 
-the app by clicking a deep link that points directly to the app's ID within Market. 
-All filtering restrictions are associated with an application's version and can
-change between versions. For example:</p> 
-
-<ul> 
-<li>If you publish a new version of your app with stricter restrictions, the app
-will not be visible to users for whom it is filtered, even if those users were
-able see the previous version.</li>
-<li>If a user has installed your application and you publish an upgrade that
-makes the app invisible to the user, the user will not see that an upgrade is
-available. </li>
-</ul>
+results and category browsing, even if a user specifically requests 
+the app by clicking a deep link that points directly to the app's ID within Market..</p>
+
+<p class="note"><strong>Note:</strong> When users browse the <a
+href="http://market.android.com">Android Market web site</a>, they can see all published
+applications. The Android Market web site compares the application requirements to each of the
+user's registered devices for compatibility, though, and only allows them to install the application
+if it's compatible with their device.</p>
+
+<p>You can use any combination of the available filters for your app. For example, you can set a
+<code>minSdkVersion</code> requirement of <code>"4"</code> and set <code>smallScreens="false"</code>
+in the app, then when uploading the app to Market you could target European countries (carriers)
+only. Android Market's filters will thus prevent the application from being available on any device
+that does not match all three of these requirements. </p>
 
+<p>All filtering restrictions are associated with an application's version and can
+change between versions. For example, if a user has installed your application and you publish an
+update that makes the app invisible to the user, the user will not see that an update is
+available.</p>
 
 
 <h2 id="manifest-filters">Filtering based on Manifest Elements</h2>
 
 <p>Most Market filters are triggered by elements within an application's
 manifest file, <a
-href="{@docRoot}guide/topics/manifest/manifest-intro.html">AndroidManifest.xml</a>,
-although not everything in the manifest file can trigger filtering.
+href="{@docRoot}guide/topics/manifest/manifest-intro.html">AndroidManifest.xml</a> 
+(although not everything in the manifest file can trigger filtering).
 Table 1 lists the manifest elements that you should use to trigger Android
 Market filtering, and explains how the filtering for each element works.</p>
 
@@ -143,29 +145,22 @@ devices.</p>
 attributes, which vary by API Level. Specifically: </p>
 
 <ul>
-<li><p>In API level 3, the <code>&lt;supports-screens&gt;</code> element itself
+<li><p>For applications that set either the <code><a
+href="{@docRoot}guide/topics/manifest/uses-sdk-element.html#min">android:
+minSdkVersion</a></code> or <code><a
+href="{@docRoot}guide/topics/manifest/uses-sdk-element.html#target">android:
+targetSdkVersion</a></code> to 3 or lower, the <code>&lt;supports-screens&gt;</code> element itself
 is undefined and no attributes are available. In this case, Market assumes that
 the application is designed for normal-size screens and shows the application to
-devices that have normal or large screens. </p>
-
-<p>This behavior is especially significant for applications that set their
-<code><a
-href="{@docRoot}guide/topics/manifest/uses-sdk-element.html">android:
-minSdkVersion</a></code> to 3 or lower, since Market will filter them from
-small-screen devices by default. Such applications can enable support for
-small-screen devices by adding a <code>android:targetSdkVersion="4"</code>
-attribute to the <code>&lt;uses-sdk&gt;</code> element in their manifest
-files. For more information, see <a
-href="{@docRoot}guide/practices/screens_support.html#strategies">Strategies for
-Legacy Applications</a>.</p></li>
-
-<li>In API Level 4, the defaults for all of the attributes is
-<code>"true"</code>. If an application does not declare a
-<code>&lt;supports-screens&gt;</code> element, Market assumes that the
-application is designed for all screen sizes and does not filter it from any
-devices. If the application does not declare one of the attributes, Market uses
-the default value of <code>"true"</code> and does not filter the app for devices
-of corresponding screen size.</li>
+devices that have normal or larger screens. </p>
+
+<li>When the either the <code><a
+href="{@docRoot}guide/topics/manifest/uses-sdk-element.html#min">android:
+minSdkVersion</a></code> or <code><a
+href="{@docRoot}guide/topics/manifest/uses-sdk-element.html#target">android:
+targetSdkVersion</a></code> is set to 4 or higher, the default for all attributes is
+<code>"true"</code>. In this way, the application is considered to support all screen sizes by
+default.</li>
 </ul>
 
     <p><strong>Example 1</strong><br />
@@ -192,6 +187,7 @@ of corresponding screen size.</li>
     Screens</a>.</p>
 </td>
   </tr>
+
   <tr>
     <td valign="top" style="white-space:nowrap;"><code><a href="{@docRoot}guide/topics/manifest/uses-configuration-element.html">&lt;uses-configuration&gt;</a></code>
       <!-- ##api level 3## --></td>
@@ -207,6 +203,7 @@ of corresponding screen size.</li>
 <p>For more details, see  <a
 href="{@docRoot}guide/topics/manifest/uses-configuration-element.html"><code>&lt;uses-configuration&gt;</code></a>.</p></td>
   </tr>
+
   <tr>
     <td rowspan="2" valign="top" style="white-space:nowrap;"><code><a
 href="{@docRoot}guide/topics/manifest/uses-feature-element.html">&lt;uses-feature&gt;</a>
@@ -237,6 +234,7 @@ href="#uses-permission-filtering"><code>&lt;uses-permission&gt;</code></a>,
 below.</p>
 </td>
   </tr>
+
   <tr>
     <td valign="top">OpenGL-ES
     Version<br />
@@ -263,6 +261,7 @@ below.</p>
 <p>For more details, see <a
 href="{@docRoot}guide/topics/manifest/uses-feature-element.html"><code>&lt;uses-feature&gt;</code></a>.</p></td>
   </tr>
+
   <tr>
     <td valign="top" style="white-space:nowrap;"><code><a href="{@docRoot}guide/topics/manifest/uses-library-element.html">&lt;uses-library&gt;</a></code></td>
     <td valign="top">Software Libraries</td>
@@ -299,6 +298,7 @@ href="{@docRoot}guide/topics/manifest/uses-feature-element.html#permissions-feat
 element.</p>
 </td>
   </tr>
+
   <tr>
     <td rowspan="2" valign="top" style="white-space:nowrap;"><code><a href="{@docRoot}guide/topics/manifest/uses-sdk-element.html">&lt;uses-sdk&gt;</a></code></td>
     <td valign="top">Minimum Framework Version (<code>minSdkVersion</code>)</td>
@@ -324,11 +324,55 @@ href="{@docRoot}guide/topics/manifest/uses-sdk-element.html#max"><code>android:m
 </table>
 
 
+
+<h3 id="advanced-filters">Advanced manifest filters</h3>
+
+<p>In addition to the manifest elements in <a href="#table1">table 1</a>, Android Market can also
+filter applications based on the advanced manifest elements in table 2.</p>
+
+<p>These manifest elements and the filtering they trigger are for exceptional use-cases
+only. These are designed for certain types of high-performance games and similar applications that
+require strict controls on application distribution. <strong>Most applications should never use
+these filters</strong>.</p>
+
+<p id="table2" class="table-caption"><strong>Table 2.</strong> Advanced manifest elements for
+Android Market filtering.</p>
+<table>
+  <tr><th>Manifest Element</th><th>Summary</th></tr>
+  <tr>
+    <td><nobr><a href="{@docRoot}guide/topics/manifest/compatible-screens-element.html">{@code
+&lt;compatible-screens&gt;}</a></nobr></td>
+    <td>
+      <p>Android Market filters the application if the device screen size and density does not match
+any of the screen configurations (declared by a {@code &lt;screen&gt;} element) in the {@code
+&lt;compatible-screens&gt;} element.</p>
+      <p class="caution"><strong>Caution:</strong> Normally, <strong>you should not use
+this manifest element</strong>. Using this element can dramatically
+reduce the potential user base for your application, by excluding all combinations of screen size
+and density that you have not listed. You should instead use the <a
+href="{@docRoot}guide/topics/manifest/supports-screens-element.html">{@code
+&lt;supports-screens&gt;}</a> manifest element (described above in <a href="#table1">table
+1</a>) to enable screen compatibility mode for screen configurations you have not accounted for
+with alternative resources.</p>
+    </td>
+  </tr>
+  <tr>
+    <td><nobr><a href="{@docRoot}guide/topics/manifest/supports-gl-texture-element.html">{@code
+&lt;supports-gl-texture&gt;}</a></nobr></td>
+    <td>
+      <p>Android Market filters the application unless one or more of the GL texture compression
+formats supported by the application are also supported by the device. </p>
+    </td>
+  </tr>
+</table>
+
+
+
 <h2 id="other-filters">Other Filters</h2>
 
 <p>Android Market uses other application characteristics to determine whether to show or hide an application for a particular user on a given device, as described in the table below. </p>
 
-<p id="table2" class="table-caption"><strong>Table 2.</strong> Application and publishing
+<p id="table3" class="table-caption"><strong>Table 3.</strong> Application and publishing
 characteristics that affect filtering on Market.</p>
 <table> <tr>
     <th>Filter Name</th> <th>How It Works</th> </tr>
@@ -365,44 +409,46 @@ developer devices or unreleased devices.</p></td> </tr> </table>
 
 
 
+<h2 id="MultiApks">Publishing Multiple APKs with Different Filters</h2>
 
-<h2 id="advanced-filters">Advanced Manifest Filters</h2>
+<p>Some specific Android Market filters allow you to publish multiple APKs for the same
+application in order to provide a different APK to different device configurations. For example, if
+you're creating a video game that uses high-fidelity graphic assets, you might want to create
+two APKs that each support different texture compression formats. This way, you can reduce the
+size of the APK file by including only the textures that are required for each device
+configuration. Depending on each device's support for your texture compression formats, Android
+Market will deliver it the APK that you've declared to support that device.</p>
 
-<p>In addition to the manifest elements in <a href="#table1">table 1</a>, Android Market can also
-filter applications based on the advanced manifest elements in table 3.</p>
+<p>Currently, Android Market allows you to publish multiple APKs for the same application only
+when each APK provides different filters based on the following configurations:</p>
+<ul>
+  <li>OpenGL texture compression formats
+    <p>By using the <a
+href="{@docRoot}guide/topics/manifest/supports-gl-texture-element.html">{@code
+&lt;supports-gl-texture&gt;}</a> element.</p>
+  </li>
+  <li>Screen size (and, optionally, screen density)
+    <p>By using the <a href="{@docRoot}guide/topics/manifest/supports-screens-element.html">{@code
+&lt;supports-screens&gt;}</a> or <a
+href="{@docRoot}guide/topics/manifest/compatible-screens-element.html">{@code
+&lt;compatible-screens&gt;}</a> element.</p>   
+  </li>
+  <li>API level
+    <p>By using the <a href="{@docRoot}guide/topics/manifest/uses-sdk-element.html">{@code
+&lt;uses-sdk&gt;}</a> element.</p>
+  </li>
+</ul>
 
-<p>These manifest elements and the filtering they trigger are for exceptional use-cases
-only. They are designed for some types of high-performance games and similar applications that
-require strict controls on application distribution. <strong>Most applications should never use
-these filters</strong>.</p>
+<p>All other filters still work the same as usual, but these three are the only filters that can
+distinguish one APK from another within the same application listing on Android Market. For example,
+you <em>cannot</em> publish multiple APKs for the same application if the APKs differ only based on
+whether the device has a camera.</p>
 
-<p id="table3" class="table-caption"><strong>Table 3.</strong> Advanced manifest elements for
-Android Market filtering.</p>
-<table>
-  <tr><th>Manifest Element</th><th>Summary</th></tr>
-  <tr>
-    <td><nobr><a href="{@docRoot}guide/topics/manifest/compatible-screens-element.html">{@code
-&lt;compatible-screens&gt;}</a></nobr></td>
-    <td>
-      <p>Android Market filters the application if the device screen size and density does not match
-any of the screen configurations (declared by a {@code &lt;screen&gt;} element) in the {@code
-&lt;compatible-screens&gt;} element.</p>
-      <p class="caution"><strong>Caution:</strong> Normally, <strong>you should not use
-this manifest element</strong>. Using this element can dramatically
-reduce the potential user base for your application, by excluding all combinations of screen size
-and density that you have not listed. You should instead use the <a
-href="{@docRoot}guide/topics/manifest/supports-screens-element.html">{@code
-&lt;supports-screens&gt;}</a> manifest element (described above in <a href="#table1">table
-1</a>) to enable screen compatibility mode for screen configurations you have not accounted for
-with alternative resources.</p>
-    </td>
-  </tr>
-  <tr>
-    <td><nobr><a href="{@docRoot}guide/topics/manifest/supports-gl-texture-element.html">{@code
-&lt;supports-gl-texture&gt;}</a></nobr></td>
-    <td>
-      <p>Android Market filters the application unless one or more of the GL texture compression formats supported by the application are also supported by the device. </p>
-    </td>
-  </tr>
-</table>
+<p class="caution"><strong>Caution:</strong> Publishing multiple APKs for the same application is
+considered an advanced feature and <strong>most application should publish only one
+APK that supports a wide range of device configurations</strong>. Publishing multiple APKs
+requires that you follow specific rules within your filters and that you pay extra attention to the
+version codes for each APK to ensure proper update paths for each configuration.</p>
 
+<p>If you need more information about how to publish multiple APKs on Android Market, read <a
+href="{@docRoot}guide/market/publishing/multiple-apks.html">Multiple APK Support</a>.</p>
diff --git a/docs/html/guide/guide_toc.cs b/docs/html/guide/guide_toc.cs
index ebf8702..fabd43e 100644
--- a/docs/html/guide/guide_toc.cs
+++ b/docs/html/guide/guide_toc.cs
@@ -406,6 +406,10 @@
       <li><a href="<?cs var:toroot ?>guide/appendix/market-filters.html">
           <span class="en">Market Filters</span></a>
       </li>
+      <li><a href="<?cs var:toroot ?>guide/market/publishing/multiple-apks.html">
+          <span class="en">Multiple APK Support</span></a>
+          <span class="new">new!</span>
+      </li>
     </ul>
   </li>
 
diff --git a/docs/html/guide/market/publishing/multiple-apks.jd b/docs/html/guide/market/publishing/multiple-apks.jd
new file mode 100644
index 0000000..ff70e85
--- /dev/null
+++ b/docs/html/guide/market/publishing/multiple-apks.jd
@@ -0,0 +1,643 @@
+page.title=Multiple APK Support
+
+@jd:body
+
+<div id="qv-wrapper">
+<div id="qv">
+
+  <h2>Quickview</h2>
+  <ul>
+    <li>Simultaneously publish different APKs for different
+device configurations</li>
+    <li>Different APKs are distributed to different devices based on filters declared in the
+manifest file</li>
+    <li>You should publish multiple APKs only when it's not possible or reasonable to
+support all desired devices with a single APK</li>
+  </ul>
+
+  <h2>In this document</h2>
+<ol>
+  <li><a href="#Concepts">Publishing Concepts</a>
+    <ol>
+      <li><a href="#Active">Active APKs</a></li>
+      <li><a href="#SimpleAndAdvanced">Simple mode and advanced mode</a></li>
+    </ol>
+  </li>
+  <li><a href="#HowItWorks">How Multiple APKs Work</a>
+    <ol>
+      <li><a href="#SupportedFilters">Supported filters</a></li>
+      <li><a href="#Rules">Rules for multiple APKs</a></li>
+    </ol>
+  </li>
+  <li><a href="#CreatingApks">Creating Multiple APKs</a>
+    <ol>
+      <li><a href="#VersionCodes">Assigning version codes</a></li>
+    </ol>
+  </li>
+  <li><a href="#SingleAPK">Using a Single APK Instead</a>
+    <ol>
+      <li><a href="#TextureOptions">Supporting multiple GL textures</a></li>
+      <li><a href="#ScreenOptions">Supporting multiple screens</a></li>
+      <li><a href="#ApiLevelOptions">Supporting multiple API levels</a></li>
+    </ol>
+  </li>
+</ol>
+
+  <h2>See also</h2>
+<ol>
+  <li><a href="{@docRoot}guide/appendix/market-filters.html">Market Filters</a></li>
+  <li><a href="{@docRoot}guide/practices/screens_support.html">Supporting Multiple Screens</a></li>
+  <li><a href="{@docRoot}sdk/compatibility-library.html">Compatibility
+Package</a></li>
+  <li><a href="{@docRoot}guide/appendix/api-levels.html">Android API Levels</a></li>
+</ol>
+
+</div>
+</div>
+
+<p>Multiple APK support is a feature in Android Market that allows you to publish different APKs
+for your application that are each targeted to different device configurations. Each APK is a
+complete and independent version of your application, but they share the same application listing on
+Android Market and must share the same package name and be signed with the same release key. This
+feature is useful for cases in which your application cannot reach all desired devices with a single
+APK.</p>
+
+<p>Android-powered devices may differ in several ways and it's important
+to the success of your application that you make it available to as many devices as possible.
+Android applications usually run on most compatible devices with a single APK, by supplying
+alternative resources for different configurations (for example, different layouts for different
+screen sizes) and the Android system selects the appropriate resources for the device at runtime. In
+a few cases, however, a single APK is unable to support all device configurations, because
+alternative resources make the APK file too big (greater than 50MB) or other technical challenges
+prevent a single APK from working on all devices.</p>
+
+<p>Although <strong>we encourage you to develop and publish a single APK</strong> that supports as
+many device configurations as possible, doing so is sometimes not possible. To help
+you publish your application for as many devices as possible, Android Market allows you to
+publish multiple APKs under the same application listing. Android Market then supplies each APK to
+the appropriate devices based on configuration support you've declared in the manifest file of each
+APK.</p>
+
+<p>By publishing your application with multiple APKs, you can:</p>
+
+<ul>
+  <li>Support different OpenGL texture compression formats with each APK.</li>
+  <li>Support different screen configurations with each APK.</li>
+  <li>Support different platform versions with each APK.</li>
+</ul>
+
+<p>Currently, these are the only device characteristics that Android Market supports for publishing
+multiple APKs as the same application.</p>
+
+<p class="note"><strong>Note:</strong> You should generally use multiple APKs to support
+different device configurations <strong>only when your APK is too large</strong> (greater than
+50MB). Using a single APK to support different configurations is always the best practice,
+because it makes the path for application updates simple and clear for users (and also makes
+your life simpler by avoiding development and publishing complexity). Read the section below about
+<a href="#SingleAPK">Using a Single APK Instead</a> to
+consider your options before publishing multiple APKs.</p>
+
+
+<h2 id="Concepts">Publishing Concepts</h2>
+
+<p>Before you start publishing multiple APKs on Android Market, you must understand a few
+concepts regarding how the Android Market publisher site works.</p>
+
+<h3 id="Active">Active APKs</h3>
+
+<div class="sidebox-wrapper">
+<div class="sidebox">
+  <h4>The difference between "Publish" and "Save"</h4>
+  <p>When editing your application, there are two buttons on the top-right side of the page. The
+first button is either <strong>Publish</strong> or <strong>Unpublish</strong> and the second
+button is always <strong>Save</strong> (but its behavior changes).</p>
+  <p>When your application is new or you have unpublished it from Market, the first
+button says <strong>Publish</strong>. Clicking it will publish any APKs listed as
+Active, making them available on Android Market. Also while your application is new
+or unpublished, clicking <strong>Save</strong> will save any changes you've made, such
+as information added to the Product details and APKs you've uploaded, but nothing is made visible on
+Android Market&mdash;this allows you to save your changes and sign out of the publisher site before
+deciding to publish.</p>
+ <p>Once you've published your application, the first button changes to
+<strong>Unpublish</strong>. Clicking it in this state unpublishes your application so that none
+of the APKs are available on Android Market. Also while published, the behavior of the
+<strong>Save</strong> button is different. In this state, clicking <strong>Save</strong> not
+only saves all your changes, but also publishes them to Android Market. For example, if you've
+already published your application and then make changes to your product details or activate new
+APKs, clicking <strong>Save</strong> makes all those changes live on Android Market.</p>
+</div>
+</div>
+
+
+<p>Before you can publish your application (whether publishing one or multiple APKs), you
+must "activate" your APK(s) from the <strong>APK files</strong> tab. When you activate an APK, it
+moves into the list of <em>Active</em> APKs. This list allows you to preview which APK(s)
+you're about to publish.</p>
+
+<p>If there are no errors, any "active" APK will be published to
+Android Market when you click the <strong>Publish</strong> button (if the application is
+unpublished) or when you click the <strong>Save</strong> button (if the application is
+already published).</p>
+
+
+<h3 id="SimpleAndAdvanced">Simple mode and advanced mode</h3>
+
+<p>The Android Market publisher site provides two modes for managing the APKs associated with
+your application: <em>simple mode</em> and <em>advanced mode</em>. You can switch between these by
+clicking the
+link at the top-right corner of the <strong>APK files</strong> tab.</p>
+
+<p>Simple mode is the traditional way to publish an application, using one APK at a time. In
+simple mode, only one APK can be activated at a time. If you upload a new APK to update
+the application, clicking "Activate" on the new APK deactivates the currently
+active APK (you must then click <strong>Save</strong> to publish the new APK).</p>
+
+<p>Advanced mode allows you to activate and publish multiple APKs that are each designed for a
+specific set of device configurations. However, there are several rules based on the manifest
+declarations in each APK that determine whether you're allowed to activate each APK along with
+others. When you activate an APK and it violates one of the rules, you will receive an error or
+warning message. If it's an error, you cannot publish until you resolve the problem; if it's a
+warning, you can publish the activated APKs, but there might be unintended consequences as to
+whether your application is available for different devices. These rules are discussed more
+below.</p>
+
+
+<h2 id="HowItWorks">How Multiple APKs Work</h2>
+
+<p>The concept for using multiple APKs on Android Market is that you have just one entry in
+Android Market for your application, but different devices might download a different APK. This
+means that:</p>
+
+<ul>
+  <li>You maintain only one set of product details (app description, icons, screenshots, etc.).
+This also means you <em>cannot</em> charge a different price for different APKs.</li>
+  <li>All users see only one version of your application on Android Market, so they are not
+confused by different versions you may have published that are "for tablets" or
+"for phones."</li>
+  <li>All user reviews are applied to the same application listing, even though users on different
+devices may have different APKs.</li>
+  <li>If you publish different APKs for different versions of Android (for different API levels),
+then when a user's device receives a system update that qualifies them for a different APK you've
+published, Android Market updates the user's application to the APK designed for the higher version
+of Android. Any system data associated with the application is retained (the same as with normal
+application updates when using a single APK).</li>
+</ul>
+
+<p>To publish multiple APKs for the same application, you must enable <strong>Advanced mode</strong>
+in your application's <strong>APK files</strong> tab (as discussed in the previous section). Once
+in advanced mode, you can upload, activate, then publish multiple APKs for the same application. The
+following sections describe more about how it works.</p>
+
+
+<h3 id="SupportedFilters">Supported filters</h3>
+
+<p>Which devices receive each APK is determined by <a
+href="{@docRoot}guide/appendix/market-filters.html">Android Market filters</a> that are specified by
+elements in the manifest file of each APK. However, Android Market allows you to publish multiple
+APKs only when each APK uses filters to support a variation of the following
+device characteristics:</p>
+
+<ul>
+  <li><strong>OpenGL texture compression formats</strong>
+    <p>This is based on your manifest file's <a
+href="{@docRoot}guide/topics/manifest/supports-gl-texture-element.html">{@code
+&lt;supports-gl-texture&gt;}</a> element(s).</p>
+    <p>For example, when developing a game that uses OpenGL ES, you can provide one APK for
+devices that support ATI texture compression and a separate APK for devices
+that support PowerVR compression (among many others).</p>
+  <br/>
+  </li>
+
+  <li><strong>Screen size (and, optionally, screen density)</strong>
+    <p>This is based on your manifest file's <a
+href="{@docRoot}guide/topics/manifest/supports-screens-element.html">{@code
+&lt;supports-screens&gt;}</a> <em>or</em> <a
+href="{@docRoot}guide/topics/manifest/compatible-screens-element.html">{@code
+&lt;compatible-screens&gt;}</a> element. You should never use both elements and you should use only
+<a href="{@docRoot}guide/topics/manifest/supports-screens-element.html">{@code
+&lt;supports-screens&gt;}</a> when possible.</p>
+    <p>For example, you can provide one APK that supports small and normal size screens and another
+APK that supports large and xlarge screens.</p>
+
+    <p class="note"><strong>Note:</strong> The Android system provides strong support for
+applications to support all screen configurations with a single APK. You should avoid creating
+multiple APKs to support different screens unless absolutely necessary and instead follow the guide
+to <a href="{@docRoot}guide/practices/screens_support.html">Supporting Multiple
+Screens</a> so that your application is flexible and can adapt to all screen configurations
+with a single APK.</p>
+    <p class="caution"><strong>Caution:</strong> By default, all screen size attributes in the <a
+href="{@docRoot}guide/topics/manifest/supports-screens-element.html">{@code
+&lt;supports-screens&gt;}</a> element are "true" if you do not declare them otherwise. However,
+because the {@code android:xlargeScreens} attribute was added in Android 2.3 (API level
+9), Android Market will assume that it is "false" if your application does not set either <a
+href="{@docRoot}guide/topics/manifest/uses-sdk-element.html#min">{@code
+android:minSdkVersion}</a> or <a
+href="{@docRoot}guide/topics/manifest/uses-sdk-element.html#target">{@code
+android:targetSdkVersion}</a> to "9" or higher.</p>
+    <p class="caution"><strong>Caution:</strong> You should not combine both <a
+href="{@docRoot}guide/topics/manifest/supports-screens-element.html">{@code
+&lt;supports-screens&gt;}</a> and <a
+href="{@docRoot}guide/topics/manifest/compatible-screens-element.html">{@code
+&lt;compatible-screens&gt;}</a> elements in your manifest file. Using both increases the chances
+that you'll introduce an error due to conflicts between them. For help deciding which to use, read
+<a href="{@docRoot}guide/practices/screens-distribution.html">Distributing to Specific Screens</a>.
+If you can't avoid using both, be aware that for any conflicts in agreement between a given size,
+"false" will win.</p>
+  <br/>
+  </li>
+
+  <li><strong>API level</strong>
+    <p>This is based on your manifest file's <a
+href="{@docRoot}guide/topics/manifest/uses-sdk-element.html">{@code &lt;uses-sdk&gt;}</a> element.
+You
+can use both the <a href="{@docRoot}guide/topics/manifest/uses-sdk-element.html#min">{@code
+android:minSdkVersion}</a> and <a
+href="{@docRoot}guide/topics/manifest/uses-sdk-element.html#max">{@code android:maxSdkVersion}</a>
+attributes to specify support for different API levels.</p>
+    <p>For example, you can publish your application with one APK that supports API levels 4 - 7
+(Android 1.6 - 2.1)&mdash;using only APIs available since API level 4 or lower&mdash;and another
+APK that supports API levels 8 and above (Android 2.2+)&mdash;using APIs available since API level 8
+or lower.</p>
+    <div class="note">
+      <p><strong>Note:</strong></p>
+      <ul>
+        <li>If you use this characteristic as the factor to distinguish multiple APKs, then the APK
+with a higher <a href="{@docRoot}guide/topics/manifest/uses-sdk-element.html#min">{@code
+android:minSdkVersion}</a> value must have a higher <a
+href="{@docRoot}guide/topics/manifest/manifest-element.html#vcode">{@code android:versionCode}</a>
+value. This is also true if two APKs overlap their device support based on a different supported
+filter. This ensures that when a device receives a system update, Android Market can offer the user
+an update for your application (because updates are based on an increase in the app version code).
+This requirement is described further in the section below about <a href="#Rules">Rules for
+multiple APKs</a>.</li>
+        <li>You should avoid using <a
+href="{@docRoot}guide/topics/manifest/uses-sdk-element.html#max">{@code
+android:maxSdkVersion}</a> in general, because as long as you've properly developed your
+application with public APIs, it is always compatible with future versions of Android. If you want
+to publish a different APK for higher API levels, you still do not need to specify the
+maximum version, because if the <a
+href="{@docRoot}guide/topics/manifest/uses-sdk-element.html#min">{@code
+android:minSdkVersion}</a> is {@code "4"} in one APK and {@code "8"} in another, devices that
+support API level 8 or higher will always receive the second APK (because it's version code is
+higher, as per the previous note).</li>
+    </ul>
+  </div>
+  </li>
+</ul>
+
+<p>Other manifest elements that enable <a
+href="{@docRoot}guide/appendix/market-filters.html">Android Market filters</a>&mdash;but are not
+listed above&mdash;are still applied for each APK as usual. However, Android Market does not allow
+you to publish multiple APKs based on variations of them. Thus, you cannot publish
+multiple APKs if the above listed filters are the same for each APK (but the APKs differ based on
+other characteristics in the manifest file). For
+example, you cannot provide different APKs that differ purely on the <a
+href="{@docRoot}guide/topics/manifest/uses-configuration-element.html">{@code
+&lt;uses-configuration&gt;}</a> characteristics.</p>
+
+
+
+<h3 id="Rules">Rules for multiple APKs</h3>
+
+<p>Before you enable advanced mode to publish multiple APKs for your application, you need to
+understand the following rules that define how publishing multiple APKs works:</p>
+
+<ul>
+  <li>All APKs you publish for the same application <strong>must have the same package
+name and be signed with the same certificate key</strong>.</li>
+
+  <li>Each APK <strong>must have a different version code</strong>, specified by the
+<a href="{@docRoot}guide/topics/manifest/manifest-element.html#vcode">{@code
+android:versionCode}</a> attribute.</li>
+
+  <li>Each APK <strong>must not exactly match the configuration support of another APK</strong>.
+    <p>That is, each APK must declare slightly different support for at least one of
+the <a href="#MarketFiltersSupported">supported Market filters</a> (listed above).</p>
+    <p>Usually, you will differentiate your APKs based on a specific characteristic (such as the
+supported texture compression formats), and thus, each APK will declare support for different
+devices. However, it's OK to publish multiple APKs that overlap their support slightly. When two
+APKs do overlap (they support some of the same device configurations), a device that falls within
+that overlap range will receive the APK with a higher version code (defined by <a
+href="{@docRoot}guide/topics/manifest/manifest-element.html#vcode">{@code
+android:versionCode}</a>).</p></li>
+
+  <li>You cannot activate a new APK that has a version code lower than that of the APK it's
+replacing. For example, say you have an active APK for screen sizes small - normal with version code
+0400, then try to replace it with an APK for the same screen sizes with version code 0300. This
+raises an error, because it means users of the previous APK will not be able to update the
+application.</li>
+
+  <li>An APK that requires a <strong>higher API level</strong> must have a <strong>higher
+version code</strong>.
+    <p>This is true only when either: the APKs differ based <em>only</em> on the
+supported API levels (no other <a href="#SupportedMarketFilters">supported market filters</a>
+distinguish the APKs from each other) <em>or</em> when the APKs do use another supported filter, but
+there is an overlap between the APKs within that filter.</p>
+    <p>This is important because a user's device receives an application update from
+Android Market only if the version code for the APK on Android Market is higher than the version
+code of the APK currently on the device. This ensures that if a device receives a system update that
+then qualifies it to install the APK for higher API levels, the device receives an application
+update because the version code increases.</p>
+<p class="note"><strong>Note:</strong> The size of the version code increase is irrelevant; it
+simply needs to be larger in the version that supports higher API levels.</p>
+    <p>Here are some examples:</p>
+    <ul>
+      <li>If an APK you've uploaded for API levels 4 and above (Android 1.6+) has a version code of
+{@code 0400}, then an APK for API levels 8 and above (Android 2.2+) must be {@code 0401} or
+greater. In this case, the API level is the only supported filter used, so the version codes
+<strong>must increase</strong> in correlation with the API level support for each APK, so that users
+get an update when they receive a system update.</li>
+      <li>If you have one APK that's for API level 4 (and above) <em>and</em> small -
+large screens, and another APK for API level 8 (and above) <em>and</em> large - xlarge screens, then
+the version codes <strong>must increase</strong>. In this case, the API level filter is used to
+distinguish each APK, but so is the screen size. Because the screen sizes overlap (both APKs
+support large screens), the version codes must still be in order. This ensures that a large screen
+device that receives a system update to API level 8 will receive an update for the second
+APK.</li>
+      <li>If you have one APK that's for API level 4 (and above) <em>and</em> small -
+normal screens, and another APK for API level 8 (and above) <em>and</em> large - xlarge
+screens, then the version codes <strong>do not need to increase</strong> in correlation with the API
+levels. Because there is no overlap within the screen size filter, there are no devices that
+could potentially move between these two APKs, so there's no need for the version codes to
+increase from the lower API level to the higher API level.</li>
+    </ul>
+  </li>
+
+</ul>
+
+<p>Failure to abide by the above rules results in an error on the Android Market publisher site
+when you activate your APKs&mdash;you will be unable to publish your application until you
+resolve the error.</p>
+
+<p>There are other conflicts that might occur when you activate your APKs, but which will result
+in warnings rather than errors. Warnings can be caused by the following:</p>
+
+<ul>
+  <li>When you modify an APK to "shrink" the support for a device's characteristics and no other
+APKs support the devices that then fall outside the supported range. For example, if an APK
+currently supports small and normal size screens and you change it to support only small screens,
+then you have shrunk the pool of supported devices and some devices will no longer see your
+application in Android Market. You can resolve this by adding another APK that supports normal size
+screens so that all previously-supported devices are still supported.</li>
+
+  <li>When there are "overlaps" between two or more APKs. For example, if an APK supports screen
+sizes small, normal, and large, while another APK supports sizes large and xlarge, there is an
+overlap, because both APKs support large screens. If you do not resolve this, then devices that
+qualify for both APKs (large screen devices in the example) will receive whichever APK has the
+highest version code.</li>
+</ul>
+
+<p>When such conflicts occur, you will see a warning message, but you can still publish your
+application.</p>
+
+
+
+<h2 id="CreatingApks">Creating Multiple APKs</h2>
+
+<p>Once you decide to publish multiple APKs, you probably need to create separate
+Android projects for each APK you intend to publish so that you can appropriately develop them
+separately. You can do this by simply duplicating your existing project and give it a new name.
+(Alternatively, you might use a build system that can output different resources&mdash;such
+as textures&mdash;based on the build configuration.)</p>
+
+<p class="note"><strong>Tip:</strong> One way to avoid duplicating large portions of your
+application code is to use a <a
+href="{@docRoot}guide/developing/projects/index.html#LibraryProjects">library project</a>. A library
+project holds shared code and resources, which you can include in your actual application
+projects.</p>
+
+<p>When creating multiple projects for the same application, it's a good practice to identify each
+one with a name that indicates the device restrictions to be placed on the APK, so you can
+easily identify them. For example, "HelloWorld_8" might be a good name for an
+application designed for API level 8 and above.</p>
+
+<p class="note"><strong>Note:</strong> All APKs you publish for the same application
+<strong>must have the same package name and be signed with the same certificate key</strong>. Be
+sure you also understand each of the <a href="#Rules">Rules for multiple APKs</a>.</p>
+
+
+<h3 id="VersionCodes">Assigning version codes</h3>
+
+<p>Each APK for the same application <strong>must have a unique version code</strong>, specified by
+the <a href="{@docRoot}guide/topics/manifest/manifest-element.html#vcode">{@code
+android:versionCode}</a> attribute. You must be careful about assigning version codes when
+publishing multiple APKs, because they must each be different, but in some
+cases, must or should be defined in a specific order, based on the configurations that each APK
+supports.</p>
+
+<h4>Ordering version codes</h4>
+
+<p>An APK that requires a higher API level must usually have a higher version code. For example, if
+you create two APKs to support different API levels, the APK for the higher API levels must have the
+higher version code. This ensures that if a device receives a system update that then qualifies it
+to install the APK for higher API levels, the user receives a notification to update the app. For
+more information about how this requirement applies, see the section above about <a
+href="#Rules">Rules for multiple APKs</a>.</p>
+
+<p>You should also consider how the order of version codes might affect which APK your users
+receive either due to overlap between coverage of different APKs or future changes you might make to
+your APKs.</p>
+
+<p>For example, if you have different APKs based on screen size, such as one for small - normal and
+one for large - xlarge, but foresee a time when you will change the APKs to be one for small and one
+for normal - xlarge, then you should make the version code for the large - xlarge APK be higher.
+That way, a normal size device will receive the appropriate update when you make the change, because
+the version code increases from the existing APK to the new APK that now supports the device. </p>
+
+<p>Also, when creating multiple APKs that differ based on support for different OpenGL texture
+compression formats, be aware that many devices support multiple formats. Because a device
+receives the APK with the highest version code when there is an overlap in coverage between two
+APKs, you should order the version codes among your APKs so that the APK with the
+preferred compression format has the highest version code. For example, you might want to perform
+separate builds for your app using PVRTC, ATITC, and ETC1 compression formats. If you prefer these
+formats in this exact order, then the APK that uses PVRTC should have the highest version code, the
+APK that uses ATITC has a lower version code, and the version with ETC1 has the lowest. Thus, if a
+device supports both PVRTC and ETC1, it receives the APK with PVRTC, because it has the highest
+version code.</p>
+
+
+<h4>Using a version code scheme</h4>
+
+<p>In order to allow different APKs to update their version codes independent of others (for
+example, when you fix a bug in only one APK, so don't need to update all APKs), you should use a
+scheme for your version codes that
+provides sufficient room between each APK so that you can increase the code in one without requiring
+an increase in others. You should also include your actual version name in the code (that is, the
+user visible version assigned to <a
+href="{@docRoot}guide/topics/manifest/manifest-element.html#vname">{@code android:versionName}</a>),
+so that it's easy for you to associate the version code and version name.</p>
+
+<p class="note"><strong>Note:</strong> When you increase the version code for an APK, Android
+Market will prompt users of the previous version to update the application. Thus, to avoid
+unnecessary updates, you should not increase the version code for APKs that do not actually
+include changes.</p>
+
+<p>We suggest using a version code with at least 7 digits: integers that represent
+the supported configurations are in the higher order bits, and the version name (from <a
+href="{@docRoot}guide/topics/manifest/manifest-element.html#vname">{@code
+android:versionName}</a>) is in the lower order bits. For example, when the application version
+name is 3.1.0, version codes for an API level 4
+APK and an API level 11 APK would be something like 0400310 and 1100310, respectively. The first
+two digits are reserved for the API Level (4 and 11, respectively), the middle two digits are for
+either screen sizes or GL texture formats (not used in these examples), and the last three digits
+are for the application's version name (3.1.0). Figure 1 shows two examples that split based on both
+the platform version (API Level) and screen size.</p>
+
+<img src="{@docRoot}images/market/version-codes.png" alt="" />
+<p class="img-caption"><strong>Figure 1.</strong> A suggested scheme for your version codes,
+using the first two digits for the API Level, the second and third digits for the minimum and
+maximum screen size (1 - 4 indicating each of the four sizes) or to denote the texture formats
+and the last three digits for the app version.</p>
+
+<p>This scheme for version codes is just a suggestion for how you should establish a
+pattern that is scalable as your application evolves. In particular, this scheme doesn't
+demonstrate a solution for identifying different texture compression formats. One option might be
+to define your own table that specifies a different integer to each of the different
+compression formats your application supports (for example, 1 might correspond to ETC1 and 2 is
+ATITC, and so on).</p>
+
+<p>You can use any scheme you want, but you should carefully consider how future versions of your
+application will need to increase their version codes and how devices can receive updates when
+either the device configuration changes (for example, due to a system update) or when you modify the
+configuration support for one or several of the APKs.</p>
+
+
+
+
+<h2 id="SingleAPK">Using a Single APK Instead</h2>
+
+<p><strong>Creating multiple APKs for your application is not the normal procedure</strong> for
+publishing an application on Android Market. In most cases, you should be able to publish your
+application to most users with a single APK and we encourage that you do so. When you encounter
+a situation in which using a single APK becomes difficult, you should carefully consider all your
+options before deciding to publish multiple APKs.</p>
+
+<p>First of all, there are a few key benefits to developing a single APK that supports all
+devices:</p>
+
+<ul>
+  <li><strong>Publishing and managing your application is easier.</strong>
+    <p>With only one APK to worry about at any given time, you're less likely to become confused by
+which APK is what. You also don't have to keep track of multiple version codes for each
+APK&mdash;by using only one APK, you can simply increase the version code with each release and
+be done.</p>  </li>
+  <li><strong>You need to manage only a single code base.</strong>
+    <p>Although you can use a <a
+href="{@docRoot}guide/developing/projects/index.html#LibraryProjects">library project</a>
+to share code between multiple Android projects, it's still likely that you'll reproduce some code
+across each project and this could become difficult to manage, especially when resolving
+bugs.</p></li>
+  <li><strong>Your application can adapt to device configuration changes.</strong>
+    <p>By creating a single APK that contains all the resources for each device configuration, your
+application can adapt to configuration changes that occur at runtime. For example, if the user docks
+or otherwise connects a handset device to a larger screen, there's a chance that this will invoke a
+system configuration change to support the larger screen. If you include all resources for different
+screen configurations in the same APK, then your application will load alternative resources and
+optimize the user experience for the new interface.</p>
+  </li>
+  <li><strong>App restore across devices just works.</strong>
+    <p>If a user has enabled data backup on his or her current device and then buys a new device
+that has a different configuration, then when the user's apps are automatically restored during
+setup, the user receives your application and it runs using the resources optimized for that device.
+For example, on a new tablet, the user receives your application and it runs with your
+tablet-optimized resources. This restore
+process does not work across different APKs, because each APK can potentially have different
+permissions that the user has not agreed to, so Android Market may not restore the application at
+all. (If you use multiple APKs, the user receives either the exact same APK if it's compatible or
+nothing at all and must manually download your application to get the APK designed for the new
+device.)</p></li>
+</ul>
+
+<p>The following sections describe some of the other options you should use to support multiple
+device configurations before deciding to publish multiple APKs.</p>
+
+
+
+<h3 id="TextureOptions">Supporting multiple GL textures</h3>
+
+<p>To support multiple types of GL textures with a single APK, your application should query the GL
+texture formats supported on the device and then use the appropriate resources or download
+them from a web server. For example, in order to keep the size of your APK small, you can query the
+device's support for different GL texture formats when the application starts for the first time and
+then download only the textures you need for that device.</p>
+
+<p>For maximum performance and compatibility, your application should use ETC1 textures wherever it
+doesn't impact the visual quality. However, because ETC1 cannot deal with images that have drastic
+chroma changes, such as line art and (most) text, and doesn't support alpha, it may not the best
+format for all textures.</p>
+
+<p>With a single APK, you should try to use ETC1 textures and uncompressed textures whenever
+reasonable, and consider the use of PVRTC, ATITC, or DXTC as a last resort when ETC1 does not
+suffice.</p>
+
+<p>Here's an example query for supported texture compression formats from inside a
+{@link android.opengl.GLSurfaceView.Renderer GLSurfaceView.Renderer}:</p>
+
+<pre>
+public void onSurfaceChanged(GL10 gl, int w, int h) {
+    String extensions = gl.glGetString(GL10.GL_EXTENSIONS);
+    Log.d("ExampleActivity", extensions);
+}
+</pre>
+
+<p>This returns a string that lists each of the supported compression formats.</p>
+
+
+
+<h3 id="ScreenOptions">Supporting multiple screens</h3>
+
+<p>Unless your APK file exceeds the Android Market size limit of 50MB, supporting multiple screens
+should always be done with a single APK. Since Android 1.6, the Android system manages most of the
+work required for your application to run successfully on a variety of screen sizes and
+densities.</p>
+
+<p>To further optimize your application for different screen sizes and densities, you should provide
+<a href="{@docRoot}guide/topics/resources/providing-resources.html#AlternativeResources">alternative
+resources</a> such as bitmap drawables at different resolutions and different layout designs for
+different screen sizes.</p>
+
+<p>For more information about how to support multiple screens with a single APK, read <a
+href="{@docRoot}guide/practices/screens_support.html">Supporting Multiple Screens</a>.</p>
+
+<p>Additionally, you should consider using a support library from the <a
+href="{@docRoot}sdk/compatibility-library.html">Compatibility Package</a> so that you can add <a
+href="{@docRoot}guide/topics/fundamentals/fragments.html">Fragments</a> to your activity designs
+when running on larger screens such as tablets.</p>
+
+
+
+<h3 id="ApiLevelOptions">Supporting multiple API levels</h3>
+
+<p>If you want to support as many versions of the Android platform as possible, you should use
+only APIs available in the lowest reasonable version. For example, your application may not require
+APIs newer than Android 2.1 (API Level 7), which makes an application available to
+over 95% of Android-powered devices (as indicated by the <a
+href="{@docRoot}resources/dashboard/platform-versions.html">Platform Versions</a> dashboard).</p>
+
+<p>By using a support library from the <a
+href="{@docRoot}sdk/compatibility-library.html">Compatibility Package</a>, you can also use APIs
+from some of the latest versions (such as Android 3.0) while
+still supporting versions as low as Android 1.6. The support library includes APIs for <a
+href="{@docRoot}guide/topics/fundamentals/fragments.html">Fragments</a>, <a
+href="{@docRoot}guide/topics/fundamentals/loaders.html">Loaders</a>, and more. Using the fragment
+APIs is particularly valuable so that you can optimize your user interface for large devices such as
+tablets.</p>
+
+<p>Alternatively, if you want to use some APIs that are available only in newer versions of Android
+(which your application can still function without), then you should consider using reflection. By
+using reflection, you can check whether the current device supports certain APIs. If the APIs are
+not available, your application can gracefully disable and hide the feature.</p>
+
+<p>Another way to use new APIs only when running on a version that supports them is to check the
+API level of the current device. That is, you can query the value of {@link
+android.os.Build.VERSION#SDK_INT} and create different code paths depending on the API level
+supported by the device. For example:</p>
+
+<pre>
+if (android.os.Build.VERSION.SDK_INT >= 11) {
+    // Use APIs supported by API level 11 (Android 3.0) and up
+} else {
+    // Do something different to support older versions
+}
+</pre>
+
diff --git a/docs/html/guide/practices/screens-distribution.jd b/docs/html/guide/practices/screens-distribution.jd
index 8be830f..951e364 100644
--- a/docs/html/guide/practices/screens-distribution.jd
+++ b/docs/html/guide/practices/screens-distribution.jd
@@ -17,6 +17,7 @@ screen configuration</li>
   <ol>
     <li><a href="#FilteringHansetApps">Filtering a Handset Application from Tablets</a></li>
     <li><a href="#FilteringTabletApps">Filtering a Tablet Application from Handsets</a></li>
+    <li><a href="#MultiApks">Publishing Multiple APKs for Different Screens</a></li>
   </ol>
 
   <h2>See also</h2>
@@ -43,7 +44,7 @@ application supports.</p>
 should understand the techniques for <a
 href="{@docRoot}guide/practices/screens_support.html">supporting multiple screens</a> and implement
 them to the best of your ability. By supporting multiple screens, your application can be made
-available to the greatest number of users with different devices, using a single {@code .apk}.</p>
+available to the greatest number of users with different devices, using a single APK.</p>
 
 
 
@@ -162,3 +163,24 @@ href="{@docRoot}guide/topics/manifest/supports-screens-element.html">{@code
 or you have decided to provide different versions of your application for different sets of screen
 configurations.</p>
 
+
+
+<h2 id="MultiApks">Publishing Multiple APKs for Different Screens</h2>
+
+<p>Although we recommend that you publish one APK for your application, Android Market allows
+you to publish multiple APKs for the same
+application when each APK supports a different set of screen configurations (as declared in
+the manifest file). For example, if you want to publish both a handset version and a tablet
+version of your application, but you're unable to make the same APK work for both screen sizes,
+you can actually publish two APKs for the same application listing. Depending on each device's
+screen configuration, Android Market will deliver it the APK that you've declared to support that
+device's screen.</p>
+
+<p>Beware, however, that publishing multiple APKs for the same application is
+considered an advanced feature and <strong>most applications should publish only one
+APK that can support a wide range of device configurations</strong>. Supporting multiple screen
+sizes, especially, is within reason using a single APK, as long as you follow the guide to
+<a href="{@docRoot}guide/practices/screens_support.html">Supporting Multiple Screens</a>.</p>
+
+<p>If you need more information about how to publish multiple APKs on Android Market, read <a
+href="{@docRoot}guide/market/publishing/multiple-apks.html">Multiple APK Support</a>.</p>
diff --git a/docs/html/guide/publishing/publishing.jd b/docs/html/guide/publishing/publishing.jd
index 7110fe5..fa677e6 100644
--- a/docs/html/guide/publishing/publishing.jd
+++ b/docs/html/guide/publishing/publishing.jd
@@ -39,7 +39,7 @@ page.title=Publishing on Android Market
 <div id="qv-extra">
   <img id="rule" src="{@docRoot}assets/images/grad-rule-qv.png">
   <div id="qv-sub-rule">
-    <img src="{@docRoot}assets/images/icon_market.jpg" style="float:left;margin:0;padding:0;">
+    <img src="{@docRoot}assets/images/icon_market.jpg" style="float:left;margin:0;padding:0 5px;">
     <h2 style="color:#669999;">Interested in publishing your app on Android Market?</h2>
     <p><a href="http://market.android.com/publish">Go to Android Market</a> to
 create a developer account and upload your application. For more information about the
diff --git a/docs/html/images/market/version-codes.png b/docs/html/images/market/version-codes.png
new file mode 100644
index 0000000..c0c9858
--- /dev/null
+++ b/docs/html/images/market/version-codes.png